Few U.S. towns have colder winter nights than Waltham
On a normal July day the thermometer tops out near 81°. The year swings widely: the coldest month’s nights and the warmest month’s afternoons are 75° apart. In July, afternoons here are cooler than in 90% of U.S. towns. Long walks are most pleasant from May to September, when afternoons reach 67–81°.
A year in Waltham at a glance
Each month’s typical high and low, and what it brings.
What stands out about Waltham’s climate
Compared with towns across the U.S., with Waltham’s place in Minnesota beside it.
What a year in Waltham feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 158 frost-free days a year
In half of years the last 32° night comes by April 30 and the first by October 5. Frost and day counts come from NOAA’s station at Austin Waste Wtp Facility, MN, 12 miles from the town’s center, 120 ft lower.
The 2023 USDA map puts Waltham’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −20°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 43 inches of snow a winter
Snow, measured at Austin Waste Wtp Facility, MN, is heaviest from January through February, about 11 inches a month. Precipitation (rain plus melted snow) adds up to 36 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 106 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Waltham
93% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Austin Waste Wtp Facility, MN.
Living with Waltham’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
158 frost-free days in zone 5a. The last frost comes by Apr 30 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 5.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 0.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Waltham from natural hazards, river flooding is the largest share (50%); heat waves, cold waves, winter storms and ice storms together are 7%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Waltham and similar climates
TownRatings has no climate map of the towns around Waltham yet.
Climates most like Waltham’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Waltham, MN | 6° | 81° | 36" | 43" |
| Hull, WI | 7° | 81° | 33" | 49" |
| Peru, NY | 9° | 80° | 35" | 50" |
| Colchester, VT | 10° | 81° | 38" | 50" |
| Hanover, NH | 9° | 82° | 39" | 61" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Waltham averaged 1.3° warmer than the 1900s. The biggest change is in December (+3.2°).
A smaller shift than in 57% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Waltham compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Waltham’s place among Minnesota’s.
Waltham weather by month
Highs, lows and precipitation from NOAA’s grid at Waltham’s center; snow, wet days and snow on the ground from Austin Waste Wtp Facility, MN. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 22° | 6° | 1.1" | 11.0" | 6 | 24 | 3° – 27° |
| February | 27° | 10° | 1.0" | 10.4" | 5 | 25 | 7° – 30° |
| March | 40° | 22° | 2.0" | 7.5" | 7 | 15 | 23° – 47° |
| April | 55° | 34° | 3.7" | 2.2" | 11 | 2 | 33° – 51° |
| May | 67° | 46° | 4.8" | 0.3" | 13 | 0 | 51° – 63° |
| June | 77° | 56° | 5.5" | 0.0" | 12 | 0 | 63° – 72° |
| July | 81° | 60° | 4.6" | 0.0" | 11 | 0 | 64° – 76° |
| August | 78° | 57° | 4.2" | 0.0" | 10 | 0 | 63° – 73° |
| September | 72° | 50° | 3.6" | 0.0" | 9 | 0 | 53° – 66° |
| October | 58° | 37° | 2.7" | 0.4" | 9 | 0 | 41° – 53° |
| November | 41° | 25° | 1.8" | 2.3" | 6 | 3 | 24° – 45° |
| December | 28° | 13° | 1.3" | 9.3" | 7 | 19 | 6° – 30° |
| Year | 54° | 35° | 36.3" | 43.4" | 106 | 88 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 23° to 47°. June is the most reliable, staying within 8°.
Where Waltham’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Waltham’s center.
- Snow: Austin Waste Wtp Facility, MN.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Austin Waste Wtp Facility, MN, 12 miles from the town’s center, 120 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Waltham’s climate
What is the weather like in Waltham?
A typical July afternoon reaches 81°, a January night drops to 6°, and about 43 inches of snow falls in a normal winter. Colder January nights than 98% of U.S. towns; cooler July afternoons than 90% of U.S. towns.
How cold does it get in Waltham in winter?
January nights average 6°. About 165 nights a year reach 32° or below and 30 reach 0° or below. In the coldest January of the last 30 years the month averaged 3°.
How much snow does Waltham get?
About 43 inches in a normal winter at Austin Waste Wtp Facility, MN, heaviest from January through February, about 11 inches a month, with snow on the ground about 88 days a year.
How hot does it get in Waltham?
July, with a typical high of 81° and a low of 60°. About 6 days a year reach 90° (Austin Waste Wtp Facility, MN).
When is the first and last frost in Waltham?
In half of years the last spring frost (32°) comes by April 30 and the first fall frost by October 5, about 158 frost-free days, at Austin Waste Wtp Facility, MN.
What growing zone is Waltham in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −20°.
What is the best time of year to visit Waltham?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Waltham getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 57% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Waltham.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.